Hello all,
I have been reading about Color case hardening on these and other forums. From my understanding, color case hardening gives a bueish purpleish color with a random pattern to the metal. When looking at Damascus steel it has the alternating color due to the forging process. So my question is, what would happen if you color case hardened Damascus? I am not trying to make the Damascus harder just add the neat color. Any thoughts?

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If you have to explain how great the idea was - it wasn't.

Carbon or stainless damascus? and what are you doing this too, a knife perhaps? What will this be used for? The whole process might wreck the tempering in the metal and it will be unsuitable for use as a tool.

Its hard to say without knowing the types of steel and possibly other metals that compose your damascus. Different steels have different tempering processes, most of which involve controlled heating or cooling for very specific lengths of time.. The issue with damascus is that it is a mixture of steels layered and forged together and then it is tempered.

I am not sure how the tempering process of damascus usually goes. Some steels are baked at 400 degrees for a couple of hours. Some are heated and quenched in oil, some are thrown in baths of liquid nitrogen.

And heating it for color case hardening will probably affect the temper.

Are you thinking about doing this to carbon or stainless damascus?

If you are working with carbon damascus, it is possible to add a patina to carbon steel by applying mustard and water to it.

Look into acid etching, I think it is the last step that is usually used on damascus knives to provide more contrast to the layers. Its a cold process that only effects the exterior of the knife whereas case hardening is a hot process.

Well I had not realized that there was a carbon and stainless type of Damascus. In reality I was thinking that the darker layers would stay the same color or be the dark color (blueish or purplish) and the lighter layers would show off more of the random swirl patterns. As for the use I was thinking about the slide of a 1911 style pistol. It sounds like it might not be as feasible as I had thought it would be.

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If you have to explain how great the idea was - it wasn't.

Is the maker Caspian Arms? If so it looks like it is a mix of 2 types of stainless steel.

what you are looking for is acid etching. managed to find this discussion of a Caspian Arms damascus 1911 slide.

Quote:

the slides caspian sells are two variations of stainless steel. as you work on them they do not show the variations - they just look like a stainless part. you must use an acid bath to bring out the damascus pattern. the acid etches the different steels at a different rate. a quick bath produces less effect than a longer bath. more polishing of the part will highlight the effect as well, slightly though. the biggest difference is the amount of time it spends in the acid bath.

General process of this is easily findable with a google search of "stainless damascus etching" most of the results will be about knives but that is ok because it is the same process.

It looks like stainless damascus can be put through hot bluing process by a gunsmith.

Acid etching and bluing can actually be done together. The link below has an example of someone putting a piece of metal through a process of acid etching, bluing, polishing, etching, bluing, and polishing.

Please note the Damascus patterns are brought out by the browning/bluing process. Usually the slow rust way of bluing. The different steels used in the barrel material will blue or rust in different ways bringing out the pattern that the gunsmith forged into the steel.

The color case hardening parts are packed in a iron/steel box with bone meal, chared leather, the whole thing is brought to temperature (red heat) and then qunched in a water bath. The water usually is agitated with air, the air and the different materials in the packing box will gine the parts the color. The color case is not very deep nor is it very durable. After the parts are quenched cleaned/fitted to the gun they are coated with a protective coating like a varnish.

There is a section on gun making in the book "The Gun by W.W. Greener"
in the text he describes how damascus steel is made and how case hardnening is done.

To get the vivid case colors each gun maker have their own ways of doing the process. They do not share what they do.

As for the use I was thinking about the slide of a 1911 style pistol. It sounds like it might not be as feasible as I had thought it would be.

Damascus steel was created in India and was used in sword making from 300 BC to 1700 AD. It is produced my layering and folding alloys of steel and forging them together. At this point in time it was the impurities in the steel that gave it its strength, the long work hammering layers together in a wood burning furnace imparted carbon to the steel between every layer.

Case hardening is from that era and it was originally used as a way of turning soft low carbon steel into a more durable soft steel encased in high carbon steel because they lacked modern metalworking processes that we have today to produce strong homogenous high carbon and steel in efficient process. Before case hardening I think they made gun barrels out of brass.

What he is working with is a piece of metal made of hundred of layers of high carbon stainless steel forged together. Case hardening would color it, but it probably wouldn't do anything to strengthen it, I think it would probably make it brittle. An acid bath would make it darker and have more contrast. Hot bluing it would basically do the came thing with ferric oxide.

I just don't think it will do anything for the appearance of the damascus other than make it dark and add some swirly colors at best.

Simple acid etching is what gives modern Damascus steel its dark/silver contrast in color. Acid etching and hot bluing would give him the visible color variation only darker. Both processes are less likely to negatively effect the temper of the metal because they don't involve heating to 1300F for 6 hours like case hardening does.

But I am going to stop because I think i am right, and so do you. But if you go to google and search for color case hardening Damascus you will find this conversation at the top of the list... Other than that it looks like most people agree that damascus steel should be acid etched or hot blued if you want to change its appearance.

Most Damascus barrels in the old days were made from rods of steel and iron twisted together. It was the different ways the steel and iron reacted to the heating that gave the result a color. Case hardening (the color was incidental) was used to harden iron frames and other parts, since iron cannot be hardened like steel can.

Needless to say, making "Damascus" made with stainless steel or treating with liquid nitrogen are modern techniques used primarily by knife makers; maybe I am ignorant, but I don't know of anyone making "Damascus" gun barrels today.

Wow. I had not expected this topic to get this much attention. So from what I read and understand color case hardening will not bring out colors that are better than acid etching and bluing and they are less durable. Good to know. Thanks for all of your input.

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If you have to explain how great the idea was - it wasn't.

Making Damascus barrels was, and still would be, a lengthy, extremely labor intensive, and hence extremely expensive, operation if done the old way, and the process probably would not be amenable to modern production methods. Strength with modern powders would, of course, also be a serious consideration as the welding seams would probably be relatively weak even if the basic material was strong steel.

Case hardening is still done in other industries because it gives a hard surface without making the steel brittle. The color, if any, is incidental. Also, various processes to chemically color steel without actually hardening it are quite common and used in reproduction guns every day.

There is no reason, other than additional expense, why any gun action cannot be case hardened, with or without color. I have seen M1911 type pistols given a color and, I admit, it is not to my taste; it just doesn't look right on a gun of that type.

Cast iron is easily hardened. It is loaded with carbon. There are high end shops doing new high pressure guns. Read an article in a machining magazine. Did not sound affordable.
A Japanese 6.5 or 7.7 action should not be case hardened. The material is very close to if not chrome molly. I don't know what kind of material a 99 Savage is, but suspect it is also chrome molly. I never had a receiver bad enough to waste it testing. I got into arguments with people that own 99's that are color cased and told them to ask their "Smith" what kind of material it was. The answer is usually "steel". Anybody that heat treats a material and does not know what it is should leave his hands off the firewrench. It is possible to boost chrome molly to 70 RC by quenching it in water. You would not want to drop it on cement.

Here's a metallurgist's comment !
Damascus [ more properly called 'pattern welded' ]is a mixture of two or more steels welded together . Many interesting patterns can be created such as a logo on a blade. While true stainless pattern welded blades are made they are difficult to do and rare. There are 'Damascus' stainless steel blades but they are made from alternating types of stainless powders compacted together.
I have a rolling block repro rifle case hardened by Turnbull , it is gorgeous !!! Color case hardening is a very difficult job requiring much experience and is used as decoration rather than hardening.

Actually, true Damascus steel in not folded and welded, rather true damascus steel as invented in india, was smelted as an ingot, and worked from the ingot. What most people think of as damascus steel is actually and correctly termed "pattern welded" steel, and is made from a process of stacking two or more different types of steel, or wrought iron, then forge welded, and manipulated in different ways to give different patterns. It can be folded, twisted, drilled, filed, and manipulated in any number of ways prior to the series of welds, to give it various patterns. The purpose of acid etching is to eat away at the differing steels and thus reveal the pattern of the layers, and this is separate from color treating, or hardening.
Another name for true damascus steel is "Wootz steel" here is a little article about using wootz to make a blade. http://www.vikingsword.com/ethsword/pat05.html

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